/*
* $Id: rvc.c,v 1.5 2002/10/27 18:27:23 luigi Exp $
******
* rvc.c - RPM Version Compare
* Given two strings representing a different version and release
* of a single rpm package, it returns which one is newer or,
* alternatively, an error.
*
* parameters
* two strings (a and b) structured in the following way:
* -.
*
* return values
* 1: a is newer than b
* 0: a and b are the same version
* -1: b is newer than a
* 2: wrong arguments number
*
* The assumption the two strings to compare are "logically coherent"
* is made, otherwise you will probably end up being told that b is
* newer than a (something which happens in this kind of situation)..
* The rpmvercmp function is "borrowed" from the Redhat package manager
* (RPM 4.1), as are all the inline functions in the header file
* (rpmvercmp.h).
*
******
*
* Copyright 2002 Luigi Bitonti
*
* Copyright 2002 Redhat Inc.
*
* This file is part of rvc (RPM version compare).
*
* rvc is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* rvc is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with rvc; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "rvc.h"
int
main(int argc, char **argv)
{
/* We need exactly two arguments for the comparison */
if (argc != 3)
{
fprintf(stderr, "Usage: %s --", argv[0]);
return 2;
}
return rpmvercmp(argv[1], argv[2]);
}
/* compare alpha and numeric segments of two versions */
/* return 1: a is newer than b */
/* 0: a and b are the same version */
/* -1: b is newer than a */
int
rpmvercmp(const char * a, const char * b)
{
char oldch1, oldch2;
char * str1, * str2;
char * one, * two;
int rc;
int isnum;
/* easy comparison to see if versions are identical */
if (!strcmp(a, b)) return 0;
str1 = alloca(strlen(a) + 1);
str2 = alloca(strlen(b) + 1);
strcpy(str1, a);
strcpy(str2, b);
one = str1;
two = str2;
/* loop through each version segment of str1 and str2 and compare them */
while (*one && *two)
{
while (*one && !xisalnum(*one)) one++;
while (*two && !xisalnum(*two)) two++;
str1 = one;
str2 = two;
/* grab first completely alpha or completely numeric segment */
/* leave one and two pointing to the start of the alpha or numeric */
/* segment and walk str1 and str2 to end of segment */
if (xisdigit(*str1))
{
while (*str1 && xisdigit(*str1)) str1++;
while (*str2 && xisdigit(*str2)) str2++;
isnum = 1;
} else {
while (*str1 && xisalpha(*str1)) str1++;
while (*str2 && xisalpha(*str2)) str2++;
isnum = 0;
}
/* save character at the end of the alpha or numeric segment */
/* so that they can be restored after the comparison */
oldch1 = *str1;
*str1 = '\0';
oldch2 = *str2;
*str2 = '\0';
/* take care of the case where the two version segments are */
/* different types: one numeric, the other alpha (i.e. empty) */
if (one == str1) return -1; /* arbitrary */
if (two == str2) return -1;
if (isnum)
{
/* this used to be done by converting the digit segments */
/* to ints using atoi() - it's changed because long */
/* digit segments can overflow an int - this should fix that. */
/* throw away any leading zeros - it's a number, right? */
while (*one == '0') one++;
while (*two == '0') two++;
/* whichever number has more digits wins */
if (strlen(one) > strlen(two)) return 1;
if (strlen(two) > strlen(one)) return -1;
}
/* strcmp will return which one is greater - even if the two */
/* segments are alpha or if they are numeric. don't return */
/* if they are equal because there might be more segments to */
/* compare */
rc = strcmp(one, two);
if (rc < 0)
return -1;
else if (rc > 0)
return 1;
/* restore character that was replaced by null above */
*str1 = oldch1;
one = str1;
*str2 = oldch2;
two = str2;
}
/* this catches the case where all numeric and alpha segments have */
/* compared identically but the segment sepparating characters were */
/* different */
if ((!*one) && (!*two)) return 0;
/* whichever version still has characters left over wins */
if (!*one) return -1; else return 1;
}